A Cascade Jet Plasma Oxidation─electroreduction System Using Pd‐Ni Dual‐Site Catalyst for Sustainable Ammonia Production from Air

Abstract Electrocatalytic N 2 reduction reaction (eNRR) has been deemed as an alternative approach to the Haber‐Bosch (H‐B) process for ammonia (NH 3 ) production, but it remains a huge challenge. Here jet plasma oxidation of N 2 is reported in air into NO x and subsequently NO 2 − coupling with electrochemical NO 2 − reduction reaction (pN 2 ─eNO 2 − RR) over PdNi alloying nanoparticles on N‐doped carbon nanotubes (PdNi/N‐CNTs) for NH 3 synthesis. The results demonstrate that the jet plasma reactor possesses excellent gas reforming capacity to achieve the largest NO 2 − yield rate of 30.46 mmol h −1 with a low energy consumption of 2.66 kWh mol N −1 . For subsequent eNO 2 − RR, PdNi/N‐CNTs can afford an NH 3 yield of 34.96 mg h −1 mg cat. −1 and a faradaic efficiency (FE) of 98.21% at −0.38 and 0.02 V (vs RHE), respectively. In situ spectroscopic characterizations combined with theoretical calculations unveil that PdNi/N‐CNTs provide Pd and Ni dual active sites, enabling NO 2 − activation on the Ni site and active H * provision on the Pd site to facilitate eNO 2 − RR. A cascade pN 2 ‐eNO 2 − RR system is constructed for sustainable NH 3 production, achieving a stable NH 3 yield rate of 25.56 mmol h −1 , an average FE >85%, as well as NO x to NH 3 conversion efficiency of 44.62% at constant ampere‐level current with finally collection of gram‐level (NH 4 ) 2 SO 4 product.